You need to activate Sage 50 Accounting.

 NOTE: Perform the following steps at the server computer if Sage 50 is on a network. 

1. Click Help, then click Sage 50 Activation, Licensing, and Subscriptions options.
2. Select Activate Online Now.
   • Try activating manually if you’re unable to activate online.
3. Close and reopen Sage 50 to complete activation.
4. Verify that you can click the Connect to a Shared Company option.